The present invention relates to a switch such as an illuminated push button switch.
As a switch of this kind, for example, an illuminated push button switch, there is a switch that, as shown in FIG. 8, comprises: a switch circuit board 21 on which a microswitch 20 is mounted and which is disposed in a lower portion; and an illumination circuit board 23 on which an LED that is not shown is mounted, and which is disposed in an upper portion so as to be opposed to a glass plate 22 serving as an operation face. The circuit boards are connected to each other by a lead wire 24. When the glass plate 22 is pressed, an operative plunger 25 is downward displaced to turn on the microswitch 20 in the lower portion. This causes the LED that is not shown and that is in the upper portion, to emit light to illuminate the glass plate 22.
In the switch of the conventional art example, however, the switch circuit board 21 on which the microswitch 20 driven by the operative plunger 25 is mounted, and the illumination circuit board 23 for illuminating the operation face must be independently disposed in the lower and upper portions, respectively. Consequently, such a switch has problems in that an extra space is required, and that the cost is high.
In the push button switch, the operation face may be excessively pressed and operated. It is desirable that internal built-in components are not detached even by a shock produced by such severe use.
The invention responds to these problems. It is a principal object of the invention to provide a switch in which the space can be reduced and the cost can be lowered. It is another object of the invention to provide a switch of high reliability in which built-in components are not detached even when a shock is applied to the switch.
In order to attain the objects, the invention is configured in the following manner.
The switch of the invention set forth in claim 1 is configured so that the switch comprises: an operating member which is displaced in accordance with an operation performed on an operation face; a switch main unit which actuates according to the displacement of the operating member; and a light source which operates according to the actuation of the switch main unit. The switch main unit and the light source are mounted on a same circuit board, and light from the light source is guided to the operation face by the operating member.
According to the invention, light from the light source is guided to the operation face by the operating member, and hence the light source and the switch main unit can be mounted on the same circuit board. As compared with the conventional art example in which individual boards are disposed, therefore, the cost can be lowered and the space can be reduced. Since light is guided through the operating member which drives the switch main unit, furthermore, it is not required to separately dispose light guiding means.
The switch of the invention is configured so that the operating member is displaceably built into the case to engage an engaging portion of the operating member with an engagement receiving portion of the case. A blocking member is disposed in an open internal space of the operating member. The blocking member abutts against an inner wall of the operating member and blocks the operating member from being bent inward, to hold the engagement state with the case.
According to the invention, the blocking member which blocks the operating member from being bent inward is disposed in the open internal space of the operating member which is displaceably built into the case. Even when a shock is applied by an excessive operation or the like, therefore, the operating member is not bent inward and the engagement state is not canceled. As a result, a switch of high reliability is obtained.
The switch of the invention is configured so that the operating member is displaceably built into the case to engage an engaging portion of the operating member with an engagement receiving portion of the case. A base on which the circuit board is mounted is coupled to the case, and a blocking portion which protrudes from the base is positioned in an open internal space of the operating member, to abut against an inner wall of the operating member. Thus, the operating member is blocked from being bent inward, to hold the engagement state with the case.
According to the invention, in order to block the operating member from being bent inward, the blocking portion which protrudes from the base is positioned in the open internal space of the operating member which is displaceably built into the case. As a result, even when a shock is applied by an excessive operation or the like, the operating member is not bent inward, the engagement state is not canceled, and a switch of high reliability is obtained.
The switch of the invention is configured so that an engaging hole is formed in the case, an engaging protrusion which is to be engaged with the engaging hole is formed on the operating member, a pair of holding grooves which hold ends of the plate-like blocking member are formed in the inner wall of the operating member, and an engagingly locking protrusion which is to be engagingly locked with an engaging hole formed in the blocking member protrudes from the inner wall of the operating member.
According to the invention, the plate-like blocking member is securely held by the holding grooves and the engagingly locking protrusion formed in the inner wall of the operating member. Therefore, the operating member can be more surely prevented from dropping off from the case.
The switch of the invention is configured so that the operating member is formed into a bottomed cylindrical shape, and built so that a bottom is positioned in an upper portion of the cylindrical case. An open end is positioned in a lower portion of the cylindrical case, slits are formed in a peripheral wall of the operating member on a side of the open end to branch the operating member into plural portions, a base on which the circuit board is mounted is fittingly coupled to the case from a lower end opening of the case, and the switch main unit mounted on the circuit board is positioned in an internal space of the operating member from the open end of the operating member.
According to the invention, slits are formed in the peripheral wall of the operating member on the side of the open end, to branch the operating member into plural portions. During a process of incorporating the operating member into the cylindrical case, therefore, the branched peripheral wall of the operating member is bent inward, so that the incorporation can be smoothly conducted. This further allows the open internal space of the operating member to be effectively used as a space for disposing the switch main unit.